Interplay of spectral efficiency, power and doppler spectrum for reference-signal-assisted wireless communication

Expressions relating spectral efficiency, power, and Doppler spectrum, are derived for Rayleigh-faded wireless channels with Gaussian signal transmission. No side information on the state of the channel is assumed at the receiver. Rather, periodic reference signals are postulated in accordance with the functioning of most wireless systems. The analysis relies on a well-established lower bound, generally tight and asymptotically exact at low SNR. In contrast with most previous studies, which relied on block-fading channel models, a continuous-fading model is adopted. This embeds the Doppler spectrum directly in the derived expressions, imbuing them with practical significance. Closed-form relationships are obtained for the popular Clarke-Jakes spectrum and informative expansions, valid for arbitrary spectra, are found for the low- and high-power regimes. While the paper focuses on scalar channels, the extension to multiantenna settings is also discussed.

BAL9141, a novel extended-spectrum cephalosporin active against methicillin-resistant Staphylococcus aureus in treatment of experimental endocarditis.

The therapeutic efficacy of BAL9141 (formerly Ro 63-9141), a novel cephalosporin with broad in vitro activity that also has activity against methicillin-resistant Staphylococcus aureus (MRSA), was investigated in rats with experimental endocarditis. The test organisms were homogeneously methicillin-resistant S. aureus strain COL transformed with the penicillinase-encoding plasmid pI524 (COL Bla+) and homogeneously methicillin-resistant, penicillinase-producing isolate P8-Hom, selected by serial exposure of parent strain P8 to methicillin. The MICs of BAL9141 for these organisms (2 mg/liter) were low, and BAL9141was bactericidal in time-kill curve studies after 24 h of exposure to either two, four, or eight times the MIC. Rats with experimental endocarditis were treated in a three-arm study with a continuous infusion of BAL5788 (formerly Ro 65-5788), a carbamate prodrug of BAL9141, or with amoxicillin-clavulanate or vancomycin. The rats were administered BAL9141 to obtain steady-state target levels of 20, 10, and 5 mg of per liter or were administered either 1.2 g of amoxicillin-clavulanate (ratio 5:1) every 6 h or 1 g of vancomycin every 12 h at changing flow rates to simulate the pharmacokinetics produced in humans by intermittent intravenous treatment. Treatment was started 12 h after bacterial challenge and lasted for 3 days. BAL9141 was successful in the treatment of experimental endocarditis due to either MRSA isolate COL Bla+ or MRSA isolate P8-Hom at the three targeted steady-state concentrations and sterilized >90% of cardiac vegetations (P < 0.005 versus controls; P < 0.05 versus amoxicillin-clavulanate and vancomycin treatment groups). These promising in vivo results with BAL9141 correlated with the high affinity of the drug for PBP 2a and its stability to penicillinase hydrolysis observed in vitro.

Copy number variation characteristics in subpopulations of patients with autism spectrum disorders.

Autism spectrum disorders (ASDs) are a heterogeneous group of disorders with a complex genetic etiology. We used high-resolution whole genome array-based comparative genomic hybridization (array-CGH) to screen 223 ASD patients for gene dose alterations associated with susceptibility for autism. Clinically significant copy number variations (CNVs) were identified in 18 individuals (8%), of which 9 cases (4%) had de novo aberrations. In addition, 20 individuals (9%) were shown to have CNVs of unclear clinical relevance. Among these, 13 cases carried rare but inherited CNVs that may increase the risk for developing ASDs, while parental samples were unavailable in the remaining seven cases. Classification of all patients into different phenotypic and inheritance pattern groups indicated the presence of different CNV patterns in different patient groups. Clinically relevant CNVs were more common in syndromic cases compared to non-syndromic cases. Rare inherited CNVs were present in a higher proportion of ASD cases having first- or second-degree relatives with an ASD-related neuropsychiatric phenotype in comparison with cases without reported heredity (P = 0.0096). We conclude that rare CNVs, encompassing potential candidate regions for ASDs, increase the susceptibility for the development of ASDs and related neuropsychiatric disorders giving us further insight into the complex genetics underlying ASDs.

Follicular Peripheral T-cell Lymphoma Expands the Spectrum of Classical Hodgkin Lymphoma Mimics.

Epstein-Barr virus (EBV)-infected B cells with Reed-Sternberg-like cell (RS) features may occur in peripheral T-cell lymphomas (PTCLs), especially in angioimmunoblastic T-cell lymphoma. Here, we report 5 patients presenting with lymphadenopathy whose first biopsies demonstrated nodular lymphoid proliferations containing scattered CD30, CD15, EBV Hodgkin and Reed-Sternberg-like cells, which led to an initial diagnosis of lymphocyte-rich classical Hodgkin lymphoma. However, the uncommon clinical features and/or the occurrence of relapse as PTCL prompted review of the biopsies with expanded immunohistologic and molecular studies and revision of the diagnoses to follicular variant of PTCL (F-PTCL). All cases had atypical small to medium-sized CD3 T cells that expressed CD10 (4/5) and the follicular helper T-cell (TFH) antigens BCL6, PD1, CXCL13, and ICOS. All demonstrated clonal T cells with a similar pattern in multiple samples from 4 patients. In 2 cases, flow cytometry demonstrated circulating lymphocytes with an abnormal sCD3, CD4, ICOS immunophenotype. Two patients had a skin rash at presentation, and 1 had B symptoms. Two of the 4 patients treated with polychemotherapy are alive at 3 and 6 years after first diagnosis. These cases highlight how some F-PTCLs may closely mimic lymphocyte-rich classical Hodgkin lymphoma requiring careful assessment of the T cells before rendering the latter diagnosis. The functional properties of TFH cells might lead to the presence of EBV-positive B blasts with RS-like features in TFH-derived PTCL such as angioimmunoblastic T-cell lymphoma and F-PTCL.

Autistic spectrum disorder: evaluating a possible contributing or causal role of epilepsy.

The onset of epilepsy in brain systems involved in social communication and/or recognition of emotions can occasionally be the cause of autistic symptoms or may aggravate preexisting autistic symptoms. Knowing that cognitive and/or behavioral abnormalities can be the presenting and sometimes the only symptom of an epileptic disorder or can even be caused by paroxysmal EEG abnormalities without recognized seizures, the possibility that this may apply to autism has given rise to much debate. Epilepsy and/or epileptic EEG abnormalities are frequently associated with autistic disorders in children but this does not necessarily imply that they are the cause; great caution needs to be exercised before drawing any such conclusions. So far, there is no evidence that typical autism can be attributed to an epileptic disorder, even in those children with a history of regression after normal early development. Nevertheless, there are several early epilepsies (late infantile spasms, partial complex epilepsies, epilepsies with CSWS, early forms of Landau-Kleffner syndrome) and with different etiologies (tuberous sclerosis is an important model of these situations) in which a direct relationship between epilepsy and some features of autism may be suspected. In young children who primarily have language regression (and who may have autistic features) without evident cause, and in whom paroxysmal focal EEG abnormalities are also found, the possible direct role of epilepsy can only be evaluated in longitudinal studies.

Spread spectrum magnetic resonance imaging.

We propose a novel compressed sensing technique to accelerate the magnetic resonance imaging (MRI) acquisition process. The method, coined spread spectrum MRI or simply s(2)MRI, consists of premodulating the signal of interest by a linear chirp before random k-space under-sampling, and then reconstructing the signal with nonlinear algorithms that promote sparsity. The effectiveness of the procedure is theoretically underpinned by the optimization of the coherence between the sparsity and sensing bases. The proposed technique is thoroughly studied by means of numerical simulations, as well as phantom and in vivo experiments on a 7T scanner. Our results suggest that s(2)MRI performs better than state-of-the-art variable density k-space under-sampling approaches.

Imaging spectrum of the solid pseudopapillary tumor of the pancreas : P42

Solid pseudopapillary tumor of the pancreas (SPPP) is a very rare pancreatic tumor with low malignancy potential, occurring mostly in adolescent females and often not considered in the differential diagnosis of pancreas tumors in children. Patients with SPPP usually present with non specific abdominal symptoms and normal clinical laboratory tests. Between 2005 and 2007, 3 cases of SPPP were evaluated in our institution. The purpose of this communication is to describe the typical imaging findings of the SPPP tumor at US, CT and MRI and to correlate the images with the macro- and microscopic features of the lesion.

Mutation spectrum of MLL2 in a cohort of Kabuki syndrome patients.

ABSTRACT: BACKGROUND: Kabuki syndrome (Niikawa-Kuroki syndrome) is a rare, multiple congenital anomalies/mental retardation syndrome characterized by a peculiar face, short stature, skeletal, visceral and dermatoglyphic abnormalities, cardiac anomalies, and immunological defects. Recently mutations in the histone methyl transferase MLL2 gene have been identified as its underlying cause. METHODS: Genomic DNAs were extracted from 62 index patients clinically diagnosed as affected by Kabuki syndrome. Sanger sequencing was performed to analyze the whole coding region of the MLL2 gene including intron-exon junctions. The putative causal and possible functional effect of each nucleotide variant identified was estimated by in silico prediction tools. RESULTS: We identified 45 patients with MLL2 nucleotide variants. 38 out of the 42 variants were never described before. Consistently with previous reports, the majority are nonsense or frameshift mutations predicted to generate a truncated polypeptide. We also identified 3 indel, 7 missense and 3 splice site. CONCLUSIONS: This study emphasizes the relevance of mutational screening of the MLL2 gene among patients diagnosed with Kabuki syndrome. The identification of a large spectrum of MLL2 mutations possibly offers the opportunity to improve the actual knowledge on the clinical basis of this multiple congenital anomalies/mental retardation syndrome, design functional studies to understand the molecular mechanisms underlying this disease, establish genotype-phenotype correlations and improve clinical management.

Imaging spectrum of the operated bladder : P41

Multiple complex procedures involving the bladder have been developed by surgeons in both children and adults, with their own advantages and drawbacks. A greater knowledge of the anatomic changes induced by each category of procedure is mandatory in the follow-up of patients and detection of early and late postoperative complications. A retrospective review of 50 pediatric and adult patients referred or treated in our institution is presented. The combined use of plain films, IVP, MCUG, US, Doppler US, CT, 3DCT and MRI is described. The imaging features are compared with surgical and anatomopathological findings. The purpose of this pictorial essay is to present a wide spectrum of diagnostic imaging findings in children and adult patients with operated bladder. The imaging features of surgical procedures with preserved, partially replaced and totally replaced bladder are described, with emphasis on a systematic multimodality approach. Learning objectives: 1) To provide an in-depth review of bladder surgical procedures with their indications, anatomopathological and imaging features. 2) To describe optimal multimodality imaging techniques for evaluating the operated bladder.

Chemical characterization and infrared spectroscopy of soil organic matter from two southern brazilian soils

Soil organic matter from the surface horizon of two Brazilian soils (a Latosol and a Chernosol), in bulk samples (in situ SOM) and in HF-treated samples (SOM), was characterized by elemental analyses, diffuse reflectance (DRIFT) and transmission Fourier transform infrared spectroscopy (T-FTIR). Humic acids (HA), fulvic acids (FA) and humin (HU) isolated from the SOM were characterized additionally by ultraviolet-visible spectroscopy (UV-VIS). After sample oxidation and alkaline treatment, the DRIFT technique proved to be more informative for the detection of "in situ SOM" and of residual organic matter than T-FTIR. The higher hydrophobicity index (HI) and H/C ratio obtained in the Chernosol samples indicate a stronger aliphatic character of the organic matter in this soil than the Latosol. In the latter, a pronounced HI decrease was observed after the removal of humic substances (HS). The weaker aliphatic character, the higher O/C ratio, and the T-FTIR spectrum obtained for the HU fraction in the Latosol suggest the occurrence of surface coordination of carboxylate ions. The Chernosol HU fraction was also oxygenated to a relatively high extent, but presented a stronger hydrophobic character in comparison with the Latosol HU. These differences in the chemical and functional group composition suggest a higher organic matter protection in the Latosol. After the HF treatment, decreases in the FA proportion and the A350/A550 ratio were observed. A possible loss of FA and condensation of organic molecules due to the highly acid medium should not be neglected.

Microvascular burden and Alzheimer-type lesions across the age spectrum.

The occurrence of microvascular and small macrovascular lesions and Alzheimer's disease (AD)-related pathology in the aging human brain is a well-described phenomenon. Although there is a wide consensus about the relationship between macroscopic vascular lesions and incident dementia, the cognitive consequences of the progressive accumulation of these small vascular lesions in the human brain are still a matter of debate. Among the vast group of small vessel-related forms of ischemic brain injuries, the present review discusses the cognitive impact of cortical microinfarcts, subcortical gray matter and deep white matter lacunes, periventricular and diffuse white matter demyelinations, and focal or diffuse gliosis in old age. A special focus will be on the sub-types of microvascular lesions not detected by currently available neuroimaging studies in routine clinical settings. After providing a critical overview of in vivo data on white matter demyelinations and lacunes, we summarize the clinicopathological studies performed by our center in large cohorts of individuals with microvascular lesions and concomitant AD-related pathology across two age ranges (the younger old, 65-85 years old, versus the oldest old, nonagenarians and centenarians). In conjunction with other autopsy datasets, these observations fully support the idea that cortical microinfarcts are the only consistent determinant of cognitive decline across the entire spectrum from pure vascular cases to cases with combined vascular and AD lesion burden.

When genetic load does not correlate with phenotypic spectrum: lessons from the GnRH receptor (GNRHR).

CONTEXT: A broad spectrum of GnRH-deficient phenotypes has been identified in individuals with both mono- and biallelic GNRHR mutations. OBJECTIVE: The objective of the study was to determine the correlation between the severity of the reproductive phenotype(s) and the number and functional severity of rare sequence variants in GNRHR. SUBJECTS: Eight hundred sixty-three probands with different forms of GnRH deficiency, 46 family members and 422 controls were screened for GNRHR mutations. The 70 subjects (32 patients and 38 family members) harboring mutations were divided into four groups (G1-G4) based on the functional severity of the mutations (complete or partial loss of function) and the number of affected alleles (monoallelic or biallelic) with mutations, and these classes were mapped on their clinical phenotypes. RESULTS: The prevalence of heterozygous rare sequence variants in GNRHR was significantly higher in probands vs. controls (P < 0.01). Among the G1-G3 groups (homozygous subjects with successively decreasing severity and number of mutations), the hypogonadotropic phenotype related to their genetic load. In contrast, subjects in G4, with only monoallelic mutations, demonstrated a greater diversity of clinical phenotypes. CONCLUSIONS: In patients with GnRH deficiency and biallelic mutations in GNRHR, genetic burden defined by severity and dose is associated with clinical phenotype. In contrast, for patients with monoallelic GNRHR mutations this correlation does not hold. Taken together, these data indicate that as-yet-unidentified genetic and/or environmental factors may combine with singly mutated GNRHR alleles to produce reproductive phenotypes.

Brain volumetric correlates of autism spectrum disorder symptoms in attention deficit/hyperactivity disorder.

Autism spectrum disorder (ASD) symptoms frequently occur in subjects with attention deficit/hyperactivity disorder (ADHD). While there is evidence that both ADHD and ASD have differential structural correlates, no study to date has investigated these structural correlates within a framework that robustly accounts for the phenotypic overlap between the two disorders. The presence of ASD symptoms was measured by the parent-reported Children's Social and Behavioural Questionnaire (CSBQ) in ADHD subjects (n = 180), their unaffected siblings (n = 118) and healthy controls (n = 146). ADHD symptoms were assessed by a structured interview (K-SADS-PL) and the Conners' ADHD questionnaires. Whole brain T1-weighted MPRAGE images were acquired and the structural MRI correlates of ASD symptom scores were analysed by modelling ASD symptom scores against white matter (WM) and grey matter (GM) volumes using mixed effects models which controlled for ADHD symptom levels. ASD symptoms were significantly elevated in ADHD subjects relative to both controls and unaffected siblings. ASD scores were predicted by the interaction between WM and GM volumes. Increasing ASD score was associated with greater GM volume. Equivocal results from previous structural studies in ADHD and ASD may be due to the fact that comorbidity has not been taken into account in studies to date. The current findings stress the need to account for issues of ASD comorbidity in ADHD.